Thanks for all the Mazal Tov wishes.
NONE of the wines were mevushal. All the guests were shabbos observant. The additional mashgiach we employed in the hall (we are pretty fussy about kashrut in large places and like peace of mind) was quite happy if he could ensure that none of the hall's staff had any contact with the wine, and they were briefed accordingly and repeatedly reminded. The mashgiach himself, together with two of the hall's staff whom he knew opened the bottles on the tables (and I helped out a bit to speed things up). We have done this before and never had a problem.
If we had to use mevushal wines only I would not have gone to any trouble and used the junk (it really was ...) in the hall!
As for the expense, I deliberately chose relatively cheap wines, with a good QPR.
For the aufruf shabbos, which was much smaller, we had more interesting stuff:
Carmel Cabernet Kayoumi 09
Yarden Merlot 09
Yarden Noble Semillon 06/Heightswine 10
Lueria Gewurtz 12
Carmel Kayoumi Riesling 10
Harei Galil Meiron 09
Yarden 2T 09
Binyamina Late Harvest Gewurtz
The aufruf was in a hotel which usually insists on mevushal, but the mashgiach was quite happy, as he knew us well, and knew there would be no problems. None of our guests would ever even dream of asking one of the waiters to open the wine for them, and the staff were all briefed beforehand in addition. In fact, part of our extra kashrus arrangements with this hotel include the stipulation that no wine is to be used for cooking, as some of our guests do not rely on pasteurisation as being good enough to be called mevushal.
I used to bring some really special wines and put them on a few select tables where they would be appreciated, but over the years I have prefered to set the bar slightly lower and give everyone the same, as I do not like the wine itself to look too conspicuous. It is part of the simcha, not the simcha itself, after all!